NEW YORK, Nov 7 (Reuters) - Many New York area residents still faced gasoline lines and empty service stations on Wednesday, while new government data confirmed that Superstorm Sandy had not caused a severe shortage of gasoline - just a dearth of power to pump it.

Commercial stockpiles of gasoline in the U.S. central Atlantic, which covers four states, including New York and New Jersey, slipped by only 310,000 barrels in the week to last Friday. That was a smaller decline than some had expected, given strong demand.

“This reflects the fact that most of the stocks stayed put because electricity was out,” said James Beck, lead analyst for the Weekly Petroleum Status report issued by the Energy Information Administration.

“Those stocks are basically frozen. You can’t get them in or out without power,” Beck added.

The data covers oil terminals, refiners and depots, but not retail tanks, many of which were shut down due to widespread power outages. Others were pumped dry as consumers rushed to fill their tanks and gas cans for portable generators.

The 1.33 percent weekly inventory decline backs up the notion that Sandy all but froze the flow of fuel through New York Harbor, the biggest and most important oil trading hub in the country. Gasoline stocks were effectively stranded at refineries, two of which remain shut, and the dozens of terminals on and near the harbor.

At just over 200,000 barrels-per-day last week, gasoline imports to the broader U.S. East Coast dropped to the lowest level since the government started collecting that data in 2004.

The drop in imports, by 300,000 bpd, corresponded to losing one tanker a day, according to Andy Lipow, president of Lipow Oil Associates, LLC.

Equally noteworthy was the glut of gasoline that formed in the U.S. Gulf Coast last week, after Colonial Pipeline shut a major conduit between Gulf refiners and the Northeast market. The Gulf Coast added 4.62 million barrels to its gasoline inventories last week.

The data reflects a snapshot of inventory levels between Friday, Oct. 26, just before the storm, and Friday, Nov. 2.

The supply situation has somewhat improved since Friday after mainline power returned to the Linden, New Jersey, fuel hub, which supplies New York and northern New Jersey. Companies like Colonial Pipeline and Nustar Energy have resumed service out of their facilities at Linden and other locations within the New York Harbor energy network.

Only eight of the 57 terminals in Sandy’s path were still shut on Wednesday, according to the federal Energy Department.

The New York Harbor was open but under alert as a powerful nor‘easter storm menaced the Northeast with rain, sleet and snow. Wind gusts could reach up to 40 miles per hour in New York on Wednesday, according to a forecast from Thomson Reuters Weather Insight.

Five oil tankers from as far away as Nigeria and Finland arrived in the New York Harbor in the last day or so and were either anchored at the port or moored at a terminal, according to live shipping data on Reuters IMAP.

Still, many gas stations were closed in the region on Wednesday and lines were long at stations that had supplies, as snow came down.

The Department of Energy said only 62 percent of service stations in the New York city metropolis had stocks to sell on Wednesday, down from 66 percent the day before.

Of five gas stations along a stretch of Rockaway Turnpike in Cedarhurst, New York, just south of Kennedy Airport, none had gas Tuesday night. When one station received a delivery Wednesday morning, people lined up, holding umbrellas in one hand and gas cans in the other while the nor‘easter dumped snow on the city.

The region’s second-largest refinery was still shut on Wednesday. Phillips 66 is assessing damage at its 238,000 barrels-per-day plant in Linden, New Jersey, which was flooded after the storm.

Hess Corp, a heavyweight in the Northeast’s energy market, said on Tuesday it was struggling to maintain adequate supplies at its New York stations with its 70,000 barrels-per-day refinery in Port Reading, New Jersey, still shut. Hess officials did not immediately respond to an inquiry on Wednesday regarding supplies.

Many Hess stations in the New York and New Jersey metro area were open, using back-up generators, a company spokesperson said.

Where some people saw shortages, others found opportunity. In Brooklyn’s Carroll Gardens neighborhood, a lone man stalked the night on Tuesday, siphoning gasoline from parked cars into plastic containers, according to a Reuters eyewitness.